[ruby/matrix] Fix Matrix#orthogonal?

2 files changed, 11 insertions, 3 deletions

diff --git a/lib/matrix.rb b/lib/matrix.rb
index 9d6650370d..7d35b61fc5 100644
--- a/lib/matrix.rb
+++ b/lib/matrix.rb
@@ -890,11 +890,12 @@ class Matrix
   #
   def orthogonal?
     raise ErrDimensionMismatch unless square?
-    rows.each_with_index do |row, i|
-      column_count.times do |j|
+
+    rows.each_with_index do |row_i, i|
+      rows.each_with_index do |row_j, j|
         s = 0
         row_count.times do |k|
-          s += row[k] * rows[k][j]
+          s += row_i[k] * row_j[k]
         end
         return false unless s == (i == j ? 1 : 0)
       end
diff --git a/test/matrix/test_matrix.rb b/test/matrix/test_matrix.rb
index 9206678261..f963b2d06a 100644
--- a/test/matrix/test_matrix.rb
+++ b/test/matrix/test_matrix.rb
@@ -800,4 +800,11 @@ class TestMatrix < Test::Unit::TestCase
     assert_equal false, @a3.unitary?
     assert_raise(Matrix::ErrDimensionMismatch) { @m1.unitary? }
   end
+
+  def test_orthogonal
+    assert_equal true, @rot.orthogonal?
+    assert_equal false, ((0+1i) * @rot).orthogonal?
+    assert_equal false, @a3.orthogonal?
+    assert_raise(Matrix::ErrDimensionMismatch) { @m1.orthogonal? }
+  end
 end